The present invention relates to the general field of systems for analyzing a biological fluid such as blood, plasma, etc.
In particular, the invention applies to blood sample analyzers, also known as hematology analyzers.
The main hematological examination known as cell counting consists in counting the cellular elements contained in blood. The main elements are red cells, white cells, and platelets. This is an important diagnosis tool for doctors and vets.
Counting is usually performed in public or private medical analysis laboratories by qualified technicians. In some countries, doctors can also perform analyses in their offices. The number of counts performed daily is extremely variable and can lie in the range a few tests per day in a doctor's office to several thousands of tests in a very large laboratory, whether private or public.
The manufacturers of analysis systems are thus obliged to make available a wide range of different systems for satisfying the particular needs of their clients. Analysis systems are characterized by their rates of throughput, the number of hematological parameters they deliver, and the extent to which they are automated.
Depending on the level of a system within a range, the rate of throughput lies in the range 60 to 120 tests per hour, with the operator having a greater or smaller number of operations to perform manually and with the parameters delivered being more or less numerous: possibly being limited to counting cells, or else extended in particular to distinguishing subfamilies of white cells.
Manifold type hydraulic circuits have been known for a long time. The use of such circuits makes it possible to diminish considerably the number of pipes needed for connecting together the hydraulic components. This reduction makes it possible to increase the reliability of the device and thus to reduce maintenance. It can also happen that the use of manifolds makes it possible to reduce the risk of leaks and to increase the ability of fluid circuits to withstand reagents.
In particular, it is known to make a biological fluid analysis system on an acrylic support that supports hydraulic components. With manifold technology, the support includes at least two plates having circuits etched therein that enable channels to be defined when the two plates are assembled together side by side. The hydraulic components then used are, in particular dilution vessels, diaphragm valves controlled by pressure/suction switching, syringes, sampling valves, diaphragm pumps, pneumatic valves for controlling integrated diaphragm valves, etc.
U.S. Pat. No. 5,788,927 describes one such system. The acrylic support described in that document serves to implement a well specified group of functions and is therefore specific to a particular system. The support is made using a relatively large number of plates assembled together side by side, and it incorporates not only channels but also dilution vessels, and diaphragm valves controlled by pressure/suction switching. The support also serves as a support for a sampling valve, for diaphragm pumps, for pneumatic valves for controlling the integrated diaphragm valves, and for a heater.
The system described in that document is very compact since numerous functions are integrated in a common acrylic support. In contrast, that system does not present any flexibility in fabrication. It is dedicated to implementing a group of functions comprising at least preparing, injecting, and analyzing the fluid, such a system not being modular, e.g. for the purpose of increasing the number of analyses that it performs in parallel. Increasing the number of analyses performed in parallel requires an entire new system to be designed and fabricated.
French patent FR 2 862 387 in the name of C2 Diagnostics also describes such a systems in the form of a block of syringes with a plastics material support for preparing, injecting, and measuring out a fluid for analysis. The syringe block is independent and operates with an air pump. Solenoid valves are also integrated in the support, which support can be connected to an optical bench by means of hydraulic circuits carried by the support.
Nevertheless, the syringe block does not provide flexibility in fabrication. As in the device proposed in U.S. Pat. No. 5,788,927, the device incorporates a predetermined plurality of functions that is not variable within a given block. To add or modify functions, it is necessary to design a new syringe block.
Thus, for a given manufacturer, since the measurement technologies and the way in which mixtures of blood and reagents are prepared are often different depending on the level of a system within a range, each system in a range made in accordance with the teaching of the prior art is thus specific, and built using its own parts and requiring maintenance that is specific thereto.